Guy W. Barcelona Jr. is a partner in Mayer Brown's Intellectual Property and Technology & IP Transactions group in Chicago. He counsels clients in a diverse array of enforcement, procurement and transactional intellectual property matters covering a variety of technological and business areas.

Guy’s trademark experience covers all aspects of prosecution and enforcement. He manages large and small portfolios throughout the clearance and filing process, and advises clients pursuing a worldwide trademark strategy. Guy has enforced and defended trademarks and domains before the US Trademark Trial and Appeals Board, US Federal Courts, and World Intellectual Property Organization.

Guy’s patent experience includes prosecution before the United States Patent and Trademark Office, defending and enforcing patents in proceedings at the United States Patent Trial and Appeal Board, and the litigation of patents in US Federal Courts and at the International Trade Commission. He has experience in all aspects of a litigation proceeding, including discovery, motion practice and trial.

Guy has applied his trademark and patent experience to his transaction practice, which includes due diligence and the sale and licensing of Intellectual Property assets.



  • Advise clients regarding the likelihood of success in pursuing enforcement actions before the U.S. Trademark Trial and Appeals Board and U.S. Federal Courts.
  • Prosecute and defend trademark infringement claims in U.S. Federal Courts, and opposition and cancellation proceedings before T.T.A.B.
  • Negotiate and draft settlement agreements regarding claims of copyright and trademark infringement.
  • Draft dispositive and non-dispositive motions, petitions for review, expert reports and expert witness statements, and invalidity and infringement contentions in U.S. Federal Courts and at the ITC.
  • Prepare witnesses for deposition and cross-examination.


  • Manage Fortune 100 portfolio, including drafting trademark clearance opinions, filing, prosecuting and maintaining U.S. and foreign marks.
  • Advise clients regarding worldwide trademark strategy.
  • Draft petitions for inter partes review before the United States Patent Trial and Appeal Board.
  • Respond to office actions in ex parte reexamination proceedings before the USPTO.
  • Counsel clients on patent validity and infringement, and aid in due diligence reviews.


  • Apply skills gained through the enforcement and procurement of Intellectual Property to due diligence and transactional matters.
  • Advise clients regarding the purchase and sale of Intellectual Property assets, including trademarks and patents.
  • Draft Intellectual Property license and sale agreements.


  • Implement comprehensive watch and enforcement program encompassing third-party trademarks and domains, including registration of gTLDs at the Trademark Clearinghouse.
  • Recover Top-Level domains through the Uniform Domain Name Dispute Resolution Policy.

Pro Bono

  • Represent client against her former employer in action under 42 U.S.C. § 1983 and 42 U.S.C. § 2000e et seq. ("Title VII"); draft pleadings, defend motion to dismiss, propound written fact. discovery, take multiple depositions, and negotiate favorable settlement.


Purdue University, BS

The John Marshall Law School, JD, cum laude
Dean's List


  • Illinois
  • Ranked World Trademark Review (WTR) 1000: US: Illinois (2023)